linux-toradex.git/include/linux/iommu.h, branch v5.19-rc3

Merge branches 'apple/dart', 'arm/mediatek', 'arm/msm', 'arm/smmu', 'ppc/pamu', 'x86/vt-d', 'x86/amd' and 'vfio-notifier-fix' into next

2022-05-20T10:27:17+00:00

iommu: Redefine IOMMU_CAP_CACHE_COHERENCY as the cap flag for IOMMU_CACHE

2022-04-28T15:24:57+00:00

While the comment was correct that this flag was intended to convey the
block no-snoop support in the IOMMU, it has become widely implemented and
used to mean the IOMMU supports IOMMU_CACHE as a map flag. Only the Intel
driver was different.

Now that the Intel driver is using enforce_cache_coherency() update the
comment to make it clear that IOMMU_CAP_CACHE_COHERENCY is only about
IOMMU_CACHE.  Fix the Intel driver to return true since IOMMU_CACHE always
works.

The two places that test this flag, usnic and vdpa, are both assigning
userspace pages to a driver controlled iommu_domain and require
IOMMU_CACHE behavior as they offer no way for userspace to synchronize
caches.

Reviewed-by: Kevin Tian 
Reviewed-by: Lu Baolu 
Acked-by: Robin Murphy 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/3-v3-2cf356649677+a32-intel_no_snoop_jgg@nvidia.com
Signed-off-by: Joerg Roedel

iommu: Introduce the domain op enforce_cache_coherency()

2022-04-28T15:24:57+00:00

This new mechanism will replace using IOMMU_CAP_CACHE_COHERENCY and
IOMMU_CACHE to control the no-snoop blocking behavior of the IOMMU.

Currently only Intel and AMD IOMMUs are known to support this
feature. They both implement it as an IOPTE bit, that when set, will cause
PCIe TLPs to that IOVA with the no-snoop bit set to be treated as though
the no-snoop bit was clear.

The new API is triggered by calling enforce_cache_coherency() before
mapping any IOVA to the domain which globally switches on no-snoop
blocking. This allows other implementations that might block no-snoop
globally and outside the IOPTE - AMD also documents such a HW capability.

Leave AMD out of sync with Intel and have it block no-snoop even for
in-kernel users. This can be trivially resolved in a follow up patch.

Only VFIO needs to call this API because it does not have detailed control
over the device to avoid requesting no-snoop behavior at the device
level. Other places using domains with real kernel drivers should simply
avoid asking their devices to set the no-snoop bit.

Reviewed-by: Lu Baolu 
Reviewed-by: Kevin Tian 
Acked-by: Robin Murphy 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/1-v3-2cf356649677+a32-intel_no_snoop_jgg@nvidia.com
Signed-off-by: Joerg Roedel

iommu: Remove iommu group changes notifier

2022-04-28T13:32:20+00:00

The iommu group changes notifer is not referenced in the tree. Remove it
to avoid dead code.

Suggested-by: Christoph Hellwig 
Signed-off-by: Lu Baolu 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20220418005000.897664-12-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

iommu: Add DMA ownership management interfaces

2022-04-28T13:32:20+00:00

Multiple devices may be placed in the same IOMMU group because they
cannot be isolated from each other. These devices must either be
entirely under kernel control or userspace control, never a mixture.

This adds dma ownership management in iommu core and exposes several
interfaces for the device drivers and the device userspace assignment
framework (i.e. VFIO), so that any conflict between user and kernel
controlled dma could be detected at the beginning.

The device driver oriented interfaces are,

	int iommu_device_use_default_domain(struct device *dev);
	void iommu_device_unuse_default_domain(struct device *dev);

By calling iommu_device_use_default_domain(), the device driver tells
the iommu layer that the device dma is handled through the kernel DMA
APIs. The iommu layer will manage the IOVA and use the default domain
for DMA address translation.

The device user-space assignment framework oriented interfaces are,

	int iommu_group_claim_dma_owner(struct iommu_group *group,
					void *owner);
	void iommu_group_release_dma_owner(struct iommu_group *group);
	bool iommu_group_dma_owner_claimed(struct iommu_group *group);

The device userspace assignment must be disallowed if the DMA owner
claiming interface returns failure.

Signed-off-by: Jason Gunthorpe 
Signed-off-by: Kevin Tian 
Signed-off-by: Lu Baolu 
Reviewed-by: Robin Murphy 
Link: https://lore.kernel.org/r/20220418005000.897664-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

iommu: Add capability for pre-boot DMA protection

2022-04-28T08:30:25+00:00

VT-d's dmar_platform_optin() actually represents a combination of
properties fairly well standardised by Microsoft as "Pre-boot DMA
Protection" and "Kernel DMA Protection"[1]. As such, we can provide
interested consumers with an abstracted capability rather than
driver-specific interfaces that won't scale. We name it for the former
aspect since that's what external callers are most likely to be
interested in; the latter is for the IOMMU layer to handle itself.

[1] https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/oem-kernel-dma-protection

Suggested-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Lu Baolu 
Signed-off-by: Robin Murphy 
Link: https://lore.kernel.org/r/d6218dff2702472da80db6aec2c9589010684551.1650878781.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel

iommu: Introduce device_iommu_capable()

2022-04-28T08:30:25+00:00

iommu_capable() only really works for systems where all IOMMU instances
are completely homogeneous, and all devices are IOMMU-mapped. Implement
the new variant which will be able to give a more accurate answer for
whichever device the caller is actually interested in, and even more so
once all the external users have been converted and we can reliably pass
the device pointer through the internal driver interface too.

Signed-off-by: Robin Murphy 
Link: https://lore.kernel.org/r/8407eb9586677995b7a9fd70d0fd82d85929a9bb.1650878781.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel

iommu: Split struct iommu_ops

2022-02-28T12:25:49+00:00

Move the domain specific operations out of struct iommu_ops into a new
structure that only has domain specific operations. This solves the
problem of needing to know if the method vector for a given operation
needs to be retrieved from the device or the domain. Logically the domain
ops are the ones that make sense for external subsystems and endpoint
drivers to use, while device ops, with the sole exception of domain_alloc,
are IOMMU API internals.

Signed-off-by: Lu Baolu 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20220216025249.3459465-10-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

iommu: Remove unused argument in is_attach_deferred

2022-02-28T12:25:49+00:00

The is_attach_deferred iommu_ops callback is a device op. The domain
argument is unnecessary and never used. Remove it to make code clean.

Suggested-by: Robin Murphy 
Signed-off-by: Lu Baolu 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20220216025249.3459465-9-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

iommu: Use right way to retrieve iommu_ops

2022-02-28T12:25:49+00:00

The common iommu_ops is hooked to both device and domain. When a helper
has both device and domain pointer, the way to get the iommu_ops looks
messy in iommu core. This sorts out the way to get iommu_ops. The device
related helpers go through device pointer, while the domain related ones
go through domain pointer.

Signed-off-by: Lu Baolu 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20220216025249.3459465-8-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel